package com.kk.base.util;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;

public class DownloadUtil {

    /**
     * 下载单文件
     * @param filePath  文件保存路径
     * @param fileName  文件本地名称
     * @param request
     * @param response
     * @throws IOException
     */
    public static void downloadFile(String filePath,String fileName,HttpServletRequest request, HttpServletResponse response) throws IOException {
        String relativeFileName=filePath+fileName;
        String s = relativeFileName.substring(relativeFileName.lastIndexOf("/") + 1);//文件名
        if (relativeFileName != null) { //设置文件路径
            File file = new File(relativeFileName); // 如果文件名存在，则进行下载
            if (file.exists()) { // 配置文件下载
                response.setHeader("content-type", "application/octet-stream");
                response.setContentType("application/octet-stream"); // 下载文件能正常显示中文
                response.setHeader("Content-Disposition", "attachment;filename=" + FileUtils.setFileDownloadHeader(request, s)); // 实现文件下载
                byte[] buffer = new byte[1024];
                FileInputStream fis = null;
                BufferedInputStream bis = null;
                try {
                    fis = new FileInputStream(file);
                    bis = new BufferedInputStream(fis);
                    OutputStream os = response.getOutputStream();
                    int i = bis.read(buffer);
                    while (i != -1) {
                        os.write(buffer, 0, i); i = bis.read(buffer);
                    }
                    System.out.println("Download the song successfully!");
                } catch (Exception e) {
                    System.out.println("Download the song failed!");
                } finally {
                    if (bis != null) {
                        try { bis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if (fis != null) {
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
    }
}
